1. The Hebrew word yom, translated “day,” is used more than 2,000 times in the Old Testament. In 95% of these cases, the word clearly means a 24-hour day, or the daylight portion of a 24-hour day. Since this is the way the word is most often used in the Old Testament, it should be understood in this way in Genesis 1 unless there are compelling reasons to prefer some other meaning.

  2. God defines what he means by “day” in Genesis 1: “God called the light ‘day’ and the darkness he called ‘night’ ” (Genesis 1:5).

  3. The terms “evening” and “morning” make it clear that normal days are being referred to in Genesis 1. These terms are used in Genesis 1:5,8,13,19,23,31.

  4. The numerical qualifier (e.g., “second day,” “third day”) demands a 24-hour day. This usage is found in Genesis 1:5,8,13,19,23,31; 2:2,3. The word “day” appears with a number over 200 times in the Old Testament, and in every case the reference is to a literal day.

  5. God established the sun and moon “to separate the day from the night,” “to mark seasons and days and years,” and “to govern the day and the night” (Genesis 1:14-18). These passages clearly refer to normal days.

  6. The Ten Commandments given to Israel were spoken by God himself, and were also written directly by God in stone (Exodus 20:1; 31:18; 32:16). Within these Ten Commandments, God described his work of creating the universe: “For in six days the LORD made the heavens and the earth, the sea, and all that is in them, but he rested on the seventh day. Therefore the LORD blessed the Sabbath day and made it holy” (Exodus 20:11). Since the Sabbath command is linked in this way to the creation week, the “days” of the creation week must be of the same kind as the “day” Israel was expected to rest.

  7. The primary reason some people want to lengthen the “days” of Genesis 1 is to make room for the evolutionary scenario, which requires billions of years. But evolution is simply incompatible with Genesis 1, and stretching the meaning of the word “day” will not accomplish the reconciliation of the creation and evolution worldviews. They are just too different. Consider the following admission by Pattle P. Pun, professor of biology at Wheaton College. (Note: Dr. Pun writes as a theistic evolutionist.)
    It is apparent that the most straightforward understanding of the Genesis record, without regard to all the hermeneutical considerations suggested by [evolutionary] science, is that God created heaven and earth in six solar days, that man was created in the sixth day, that death and chaos entered the world after the Fall of Adam and Eve, that all of the fossils were the result of the catastrophic universal deluge which spared only Noah’s family and the animals therewith. (Journal of the American Scientific Affiliation, March 1987, p. 14)

  8. In the New American Standard Bible, Genesis 2:4 says: “This is the account of the heavens and the earth when they were created, in the day that the LORD God made earth and heaven.” Here is an instance where the word “day” does not refer to a 24-hour day. The phrase “in the day that” is a Hebrew idiom meaning “at the time that” or simply “when” (as the phrase is rendered in the New International Version). But this usage does not invalidate our understanding of “day” meaning a 24-hour day (or the light portion thereof) in Genesis 1. In fact, a similar occurrence of this idiom appears in Numbers 7:84 (see NASB margin), which follows twelve literal days of offerings (Numbers 7:12-83).

  9. II Peter 3:8 says, “With the Lord a day is like a thousand years, and a thousand years are like a day.” But this is a simile (a literary device used for comparison) given to help us understand the Lord’s patience, not a hint as to how we should interpret Genesis 1. The word “like” is not the same as an equal sign! Also: the word “day” is unlikely to carry a figurative meaning in Genesis 1 since it appears for the very first time there. Words are used figuratively only after their literal meaning is well established.

(Reference: Impact # 81, “Theistic Evolution and the Day-Age Theory,” by Richard Niessen)